Electrical projectile priming device



Oct. 8, 1963 HANS-DIETER HAia'NKU-ETAL 3,106,160 ELECTRICAL PROJECTILEPRIMINGDEVICE 1 Filed Nov. 3', 1960 jm emor's H-ziw Dtaz;. Hal-771aHermann, Rermer B y 3,106,160 ELECTRICAL PRQJECTLE PRlltlmG DEVICEHans-Dieter I-larnau, Gevelsberg, and Hermann Kennel", Dusseldorf,Germany, assigncrs to Firma Rheinmetall G.m.b.ll., Dusseldorf, GermanyFiled Nov. 3, 1960, eer. No. 67,068 (Ilaims priority, applicationGermany Nov. 6, 15 59 11 (Balms. ((11. 132-702) This invention relatesto an electrical projectile priming device for several successivepriming operations, in particular for projectiles with separate primingof their pro pellant section and their operative section. The device ofthe invention is distinguished from hitherto known electrical projectilepriming devices mainly by an impulse generator, preferably incorporatedin the firing weapon, and by a firing circuit of special design, locatedin the projectile and coupled to the impulse generator, for thetriggering of the two half-waves which are being inductively generatedin the coupling coil of the firing circuit of the projectile uponactuation of the impulse generator.

In further development of the invention, safety arrangements guardingagainst any faults which may occur are provided in the weapon as well asin the firing circuit of the projectile, and a possibility of checkingthe functioning of the device has also been provided.

The projectile priming device proposed by the present invention offersthe advantage of a very high degree of safety in transit and safetyagainst premature actuation shortly in front of the bore of the weapon.

The details of the invention will be understood from the description ofan illustrated example of an electric circuit of a priming device.

The priming device comprises two section, i.e. the section Iincorporated in the weapon and the firing circult lI located in theprojectile. In this way, absolute safety in transit is achieved.

The section I incorporated in the weapon comprises an impulse generator1 to which are connected a capacitor 2 and a coupling coil 3 via arectifier 22.

he firing circuit It comprises a coupling coil 4. Both sections I and IIare inductively coupled to one another after loading, by means of thecoupling coils 3 and 4.

The coupling coil 3, together with the capacitor 2 forms a parallelresonant circuit coupled to the output of impulse generator 1. Thisresonant circuit is tuned to the characteristic frequency of thegenerator for the purpose of an improved transmission of energy. Onactuation of the impulse generator 1, a pulse is transmitted to thecoupling coil 3 whereby an oscillation with a positive and a negativehalf-wave is induced in the coupling coil 4.

According to the invention these two hallfovaves are utilized for twosuccessive priming operations. The first positive half-wave charges thepre-storage condenser 6 by way of the rectifier 5. The second negativehalf wave ignites the propellant section of the projectile by way of therectifier 7 and the primer 8.

During the subsequent period of acceleration for the projectile, theacceleration switch 9 closes the resonant circuit comprising thecondensers 6, 1d and the inductance 11 which leads to an oscillatingdischarge of the condenser 6, said discharge being already interrupted,however, after a quarter cycle by means of the rectifier 12, so that theintermediate storage condenser 10 retain-s nite .1' States atent ice 2maximum charge potential. By including the inductance 11 and therectifier 12 (transfer intensifier) in the circuit, almost the entireenergy is transferred from the condenser 6 to the condenser Ill, withthe exception of small losses in the inductance 11, and only a veryshort-duration contact in the acceleration switch 9 is required toeffect this transfer, since the resonant circuit may be tuned forhigh-frequency operation. The upper limit of the frequency is defined bythe switching capacity of the rectifier .12. It is chosen in such a way,however, that upon closing of the switch 9 the pre-storage circuit 4-, 6which is tuned to the frequency of the initial resonant circuit 2, 3, isbeing de-tuned such that the priming capacitor 14 can under nocircumstances receive a potential sulficiently high to effect priming.

Thereafter the condenser 10 discharges with delay into the condenser 14via the resistance 13. In this way the barrel safety which is requiredaccording to the type of the projectile and its employment, isguaranteed because the primer 15 will only have been prepared when thecondenser 14 has attained its (full priming potential. In the primingcircuit is also included a rectifier 18 which only passes currentthrough the primer 15 when the condenser 14 begins to act as a potentialsource (ignition by impacting on target). The device is safeguardedagainst any faults which may occur in the following way:

If the transfer of the charge of condenser 6 is not effected within thevery short time provided for the dispatch of the projectile (propellantfailure), then, if the switch 9 is closed later on by mechanical impact(unloading etc.), said condenser whose potential will have dissipatedthrough the leak resistance 19, will no longer have the potentialnecessary to initiate the priming of the operative section.

If the two nose halves 16, 17 constituting the nose contactor have beendamaged prior to firing so that both nose halves 16, 17 have connectedso as to conduct current, the condenser 6 is short circuited via the twonose halves 16, 17 and the rectifier 2t In this case the projectileleaves the barrel as a dud.

If the contactor nose 16, 17 is damaged during the barrel safetyinterval, ignition of the operative section can still not take placebecause the condenser 16 is then discharged via the nose halves 16, 17and the rectifier 241, i.e. the transfer of the charge from condenser 10to condenser 14 is terminated before the requisite priming volt age isattained. The energy with which the capacitor 14 has been charged up tothen is compensated via the two nose-halves 16, 17, the rectifier 21 andthe resistance 13.

Since the timing operation can only be triggered by the inductivetransmission of a potential impulse originating in the impulse generator1, which is located in the weapon, the transport safety of theprojectile is guaranteed in any case.

Prior to being assembled in the projectile, every priming device can beaccurately tested for functioning in a simple manner, since the circuitpoints required for testing have been made accessible from without toenable the operational elements (contact hoods and primer connections)to be connected.

To carry out a test, it is possible for example t transmit the potentialimpulse in the usual manner to the coupling coil 4 and to connect thecondenser 14 to the input of an oscillograph via the screw fitting forthe primer and the primer thread (connection for 17), so that the chargecharacteristic for condenser 14 is rendered visible, whichcharacteristic should be confined within predetermined limit curves.

In this operation, the second half-wave (connections made at -8) promptsa short mechanical impact which actuates the acceleration switch 9.

The behaviour of the primers in the case of premature contacting of thehoods may for example be ascertained by means of a timed switch, notshown in the drawing, which is connectedto the leads of the contactinghoods 16, 17.

What we claim is:

1. An electrical priming device for a projectile having a propellantsection connected to an operative section, comprising means forreceiving a signal having an alternating waveform, a signal storage andtransfer circuit and a firing circuit for theoperative section, saidstorage and transfer circuit including a first capacitor and means fortransferring charge from the first capacitor to said firing circuit, apriming device for said propellant section, means for routing thepositive half-wave of said signal to charge said first capacitor, andmeans for routing the negative half-wave of said signal to actuate saidpropellant section priming device.

2. An electrical priming device for a projectile according to claim 1,in which the operative section storage and transfer circuit includes asecond capacitor and acceleration responsive means for connecting saidfirst and second capacitors for transfer of charge from the firstcapacitor to said second capacitor.

3. An electrical projectile priming device according to claim 2 in whichthe operative section storage and trans fer circuit includes a thirdcapacitor and a resistor, said third capacitor and said resistor beingconnected in series across the second capacitor.

4. An electrical projectile priming device according to claim 1, inwhich said firing circuit includes a priming means and an impactcontactor, first and second contacts for said contactor closable inresponse to an impact, said contactor and priming means connected tosaid storage and transfer circuit for the receipt of an actuating signaltherefrom upon closure of said first and second contacts.

5. A firing device according to claim 1, including an impulse generatorand an input oscillator circuit coupled to said impulse generator, saidgenerator and oscillator circuit being located in said operativesection.

6. An electrical priming device for a projectile having a propellantsection and an operative section, said device including means forreceiving a signal having an alternating waveform, an electrical chargestorage and transfer circuit and a firing circuit for said operativesection, said charge storage and transfer circuit having first, secondand third charge storage means, acceleration responsive means fortransferring charge from said first to said second charge storage means,said second and third charge storage means being connected via chargetransfer delay means, said firing circuit including a priming meansconnected in series with an impact contactor, first and second contactsfor said contactor closable in response to an impact, said seriesconnected contactor and priming means connected to said third chargestorage means for discharging said discharge storage means to actuatesaid firing device upon closure of said first and second contacts, andmeans for routing the positive half-cycle of the received signal tocharge said first charge storage means, a propellant section primingmeans and means for routing the negative half-cycle of the receivedsignal to actuate said propellant section priming means.

7. An electrical projectile priming device according to claim 6, andincluding first means connected between said impact contactor and saidfirst'charge storage means to permit discharge thereof upon closure ofsaid first and second contacts prior to operation of said accelerationresponsive means, and second means connected between said impactcontactor and second storage means and providing a discharge paththere-for upon closure of said first and second contacts.

8. An electrical priming device for a projectile having a propellantsection coupled to an operative section, including a coil for receivinga signal having an alternating waveform, :an electrical charge storageand transfer circuit and a fining circuit for said operative section,said charge storage and transfer circuit including first, second andthird capacitors, acceleration responsive means for connecting saidfirst and second capacitors to permit transfer of charge from said firstcapacitor to said second capacitor, a delay resistor connected in serieswith said third capacitor, said series connected delay resistor andthird capacitor connected across the second capacitor, said firingcircuit including a primer, a rectifier and an impact contactor havingfirst and second contacts, said primer being connected in series withsaid first and second contacts and with said rectifier, the thirdcapacitor being connected to said rectifier, said rectifier being poledto permit discharge of said third capacitor through 7 said primer uponclosure of said first and second contacts, said primer being actuableonly if said third capacitor is charged above a predetermined level, asecond primer connected in said propellant section, first and secondrouting rectifiers, said coil connected in series with" said firstrouting rectifier and across said first capacitor, said coil furtherbeing connected in series with said second routing rectifier and acrosssaid second primer, said first and second routing devices being poled sothat the positive half-cycle of the received signal is routed via saidfirst routing rectifier to charge said first capacitor, and saidnegative half-cycle of said received signal is routed via said secondrouting rectifier to actuate said second primer.

9. An electrical projectile priming device according to claim 8, andincluding an acceleration responsive switch, an inductance and arectifier all connected in series and between one side of said firstcapacitor and one side of said second capacitor, so that closure of saidswitch allows charge to be transferred from said first to said secondcapacitor.

10*. An electrical projectile priming device according to claim 8 andincluding a resistor connected in parallel with said first capacitor, afirst capacitor discharging rectifier connected in series with saidfirst and second contacts across said first capacitor and poled topermit discharge of said first capacitor on closure of said first andsecond contacts prior to operation of said acceleration responsive meansto transfer charge from said first to said second capacitor, 3. secondcapacitor discharge rectifier connected in series with said first andsecond contacts across said second capacitor and poled to permitdischarge of said second capacitor on closure of said first and secondcontacts.

11. An electrical projectile priming apparatus comprising an impulsegenerator, a resonant circuit including a capacitor and an inductorconnected in parallel, a rectifier, said impulse generator connected inseries with the rectifier to said parallel resonant circuit to supplyunidirectional impulses thereto, the resonant circuit forming analternating signal having a frequency equal to the frequency of theimpulse generator in response to a pulse from said generator, areceiving coil coupled to said parallel resonant circuit inductor, asecond capacitor connected in parallel with said receiving coil todefine a signal receiving parallel tuned circuit having a resonantfrequency equal to that of the signal generating resonant circuit and anacceleration responsive switch coupled to said receiving coil, saidresonant circuit comprising a first and a second charge storingcapacitor and having a resonant frequency such that it is stronglydetuned relative to the signal receiving tuned circuit upon closure 5 ofsaid acceleration responsive switch, the combination funfiher includinga rectifier connected in series between said first and said secondcharge storing capacitors whereby closure of said accelerationresponsive switch a llows charge to be transferred from said first tosaid sec- 5 0nd storing capacitor.

2,514,359 Allison July 11, 19-50 6 Brode Mar. 13, 1956 Small l Aug. 25,1959 Bleakney Sept. 8, 1969 Kidd Jan. 19, 1960 Ruehlemann Mar. 1, 1960Ruehlemann Sept. 5, 1961 FOREIGN PATENTS Germany May 6, 1959

1. AN ELECTRICAL PRIMING DEVICE FOR A PROJECTILE HAVING A PROPELLANTSECTION CONNECTED TO AN OPERATIVE SECTION, COMPRISING MEANS FORRECEIVING A SIGNAL HAVING AN ALTERNATING WAVEFORM, A SIGNAL STORAGE ANDTRANSFER CIRCUIT AND A FIRING CIRCUIT FOR THE OPERATIVE SECTION, SAIDSTORAGE AND TRANSFER CIRCUIT INCLUDING A FIRST CAPACITOR AND MEANS FORTRANSFERRING CHARGE FROM THE FIRST CAPACITOR TO SAID FIRING CIRCUIT, APRIMING DEVICE FOR SAID PROPELLANT SECTION, MEANS FOR ROUTING THEPOSITIVE HALF-WAVE OF SAID SIGNAL TO CHARGE SAID FIRST CAPACITOR, ANDMEANS FOR ROUTING THE NEGATIVE HALF-WAVE OF SAID SIGNAL TO ACTUATE SAIDPROPELLANT SECTION PRIMING DEVICE.